here are pics of intake manifold off my sierra 2500, engine is 8.1L. This has the closed or interal pcv system, requires no maintenance. I did some researching and there are complaints of 8.1L burning oil, whether or not it's due to the pcv system i don't know. But i'm wondering if i should block this off and set up a traditional external pcv system. The whole inside of my intake is coated in a brown oil varnish, i don't know if that's normal. I recently bought this truck, haven't put more than 1000 miles on it before jack standing it to fix an exhaust leak. so i really don't know if it's an oil burner. I've been going to town on everything under the hood to fix things right and for the last time... have injectors getting cleaned and hope to get more than 11 mpg when finally finished. But i don't want to put the intake back on and later have to pull it again, gaskets are $70. I also had what looks like ash deposits on the spark plugs, they were not oil fouled and were clean and whitish. so i don't know if that might have been previous owner using fuel additives, will post pics of spark plugs when i can
http://www.gm-trucks.com/forums/index.php?showtopic=90812
http://www.gm-trucks.com/forums/index.php?showtopic=90812
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